There has long stood a battle between chiropractors on the topic of subluxation. On this one word, the definition of a chiropractor is defined. In the early days of chiropractic, it was theorized that all diseases in the human body were the direct effects of a misalignment of the vertebral bodies (back bones). The Palmers, the founders of chiropractic, hypothesized that the bones of the back were at risk for dislocating. By dislocating, I mean very minute small dislocation, thus the term; subluxation. It was thought that the misalignment of these structures caused pressure on a spinal nerve which directly innervated a muscle, joint, organ etc… This pressure would cause a decrease in “nerve flow” aka: foot on the hose analogy. The chiropractor would then use his hands, instruments, x-ray films, or all of the above to locate the subluxation. He would deliver a high velocity, low amplitude thrust to the vertebrae which would put it back into correct alignment usually accompanied with a “crack” or “cavitation” as we define it. This was a beautiful theory filled with flowery slogans such as, “The power that made the body, heals the body.”However, 100+ years later we live in a far different world. We have the technology available to prove or disprove theories that were held to be sacred and true during the 19th and 20th century. The best research that we have available clearly indicates that when a chiropractor manipulates a joint, there is no displacement of structures. In other words, bones don’t go out of place (that’s called a dislocation) and chiropractors do not move bones back in. Research also shows that it’s practically impossible for a vertebrae to compress a spinal nerve. One would think that this new found research would destroy chiropractic…. but it hasn’t.
The majority of chiropractors still claim that bones move out of alignment and cause nerve compression. A good portion of these chiropractors know that this isn’t quite what happens, but they describe it this way to patients because they think it’s easier to understand. There are however, still chiropractors that claim that spine misalignment is the root cause of all disease and that by having your spine adjusted you lower your chances of contracting such diseases. This is one of the main reasons the medical professional labeled chiropractors “cult practitioners” in the early 20th century. There has been a lot of good research that has demonstrated that spinal manipulative therapy is more effective at treating back pain, neck pain and tension headaches then pain medication and rest. Nowadays, more and more MD’s and DO’s are referring their patients to chiropractors in light of these studies. There have been countless case studies that have shown that chiropractic care has had positive effects on non-musculoskeletal conditions such as hypertension, colic, etc… but as of today there is no solid evidence for why chiropractic helps conditions other than musculoskeletal dysfunctions. At this time, the placebo effect seems to be the best scientific answer for why chiropractic helps with so many ailments.
So if we don’t move bones, what do we do, and what is that sound when we manipulate your spine? Well first thing is first, the sound that generally accompanies a spinal manipulation is the rapid release of oxygen, nitrogen, and carbon dioxide from the synovial facet joints of the spine. The sound the spine makes when being manipulated is the same sound you hear when you pop your knuckles. When joints don’t move because of poor posture, soft tissue injuries, etc… those joints tend to become tender, or possibly even painful. One of the reasons patients report such pain relief after a manipulation is simply because the joint can now move with less restriction. Chiropractic philosophy has long held that the body is a self-healing, self-regulating organism that simply needs correct spinal alignment in order to function at optimal levels. There is no adequate research to substantiate this claim and this concept is has been labeled as non-scientific and quackery by the American Medical Association.
David Seaman DC MS, a chiropractor and clinical nutritionist, has proposed an alternate hypothesis for why chiropractic may positively affect the nervous system. For the sake of simplicity I’ll give a brief synopsis of what Seaman has hypothesized. Seaman hypothesizes that the spinal manipulation stimulates mechanoreceptors in the spinal joints due to the quick increase in joint motion. This starts a reflex arc that sends non-pain receptors (A-alpha and A-Beta) to the central nervous system which in turn relaxes the joint and the surrounding soft tissues. Seaman’s idea is basically that people are running around with their sympathetic (fight or flight) nervous system engaged most of the time. People are constantly running on adrenaline with their busy schedules and the stresses of daily life. The reflex mechanism caused by the manipulation is thought to decrease sympathetic activity and increase the activity of the parasympathetic nervous system (rest and digest). When the parasympathetic nervous system is the the dominant system running in the body, healing is prioritized much more so then during a fight or flight (sympathetic) state. This could explain why multitudes of patients have reported that chiropractic has helped them with diseases that traditional medical care has not been successful with. There is currently research being conducted in Canada to prove seaman’s hypothesis. The science of the CNS reflex is well documented and excepted in the scientific community. What researchers will have to prove is if spinal manipulation actually stimulates these mechanoreceptors that start the whole reflex mechanism.
There is much that is still unknown in the chiropractic profession. I’m the first to admit that you research has limits in what it can reliably measure. However, research is responsible for some of the greatest medical advancements in recent history and continues to be invaluable in many areas. We may never know exactly what takes place when a chiropractor places his hands on a patient and delivers that high velocity, low amplitude thrust, but I think chiropractic will be around for a long time for the simple fact that it works.
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